The present invention relates to a wide-angle photographic lens having an aperture ratio of 1:2.8 and a focal length of 28 mm for use in 35 mm photographic cameras. It is an object of the present invention to provide a small-size high-performance lens system having lenses that can easily be shaped and are made of an optical material which can be fabricated with ease and is inexpensive.
Many lens systems of the class described have been known in the art. They can roughly be classified into positive-front-lens systems having a positive first lens component and negative-front-lens system having a negative first lens component. The former lens system is effective for correcting distortions, but has a tendency to cause variations in the curvature of field when the lens system is close to the object. The present invention is directed to a lens system of the latter type, although not of a super-miniaturized size, is an improvement that meets three conditions of compactness, high performance, and low cost.